The electricity transmission line is realized by boosting the power generated by the generator with a transformer, and then connecting it to the power transmission line through control equipment such as a circuit breaker. Many problems will affect the normal operation of the electricity transmission line. Let's take a closer look.
There is a high probability of being struck by lightning in the thunderstorm season. There are three cases of lightning strikes on the line:
1. Lightning strikes on the cable connectors to produce a direct lightning overvoltage;
2. Lightning strikes on the lightning protection line and strikes back on the power line;
3. Lightning strikes near the line or on the towers, which induces overvoltages on the electricity transmission line.
Whether it is a direct strike overvoltage or an induced overvoltage, a large amount of charge is generated on the wire, and these charges propagate on the guide wire at a speed close to the speed of light (300,000 kilometers per second), which is the lightning wave.
When lightning strikes overvoltage directly, the insulators of the line are likely to be flashed, which may cause single-phase grounding or tripping of the line, and even more serious may cause accidents such as insulator breakage, breakdown, disconnection, etc., which may cause the power supply to be interrupted for a long time.
Lightning strikes the substations and threatens the insulation of electrical equipment. This causes accidents such as lightning arrester explosion and transformer insulation damage, which directly affects the safe operation of the substation.
In low temperature rain and snow day, due to high humidity, a large amount of water and gas condensed on the wire surface. This can easily cause freezing disasters in the power system.
When the wired is covered, the tension on both sides of the pole is unbalanced, and the wire will be broken due to the impact of the load. The icy wire will shrink when it is cold, and the wind will cause shock, the wires, towers, insulators and metal fittings will also suffer fatigue damage due to unbalanced impact.
Transmission line collapse, disconnection and trip accidents will cause significant damage to the transmission lines of the power system, and threaten the safe and stable operation of the power grid and the reliability of the operation of the power supply system.
The external forces destroying power lines is more complex and widely distributed. In mountainous areas, blasting rocks can easily damage insulators and break wires; burning crops underneath the line, flames and smoke can easily cause the line to trip; large cranes and excavators operating in the line protection area sometimes break the wires and so on; some criminals are driven by economic interests to steal power facilities such as towers and cables; and fishing under power transmission lines and illegal construction are external forces that damage power lines.